Heat the oven to 180C/160C fan/gas 4 and lightly oil a 2-litre ovenproof dish. Cut off the neck of the squash, about two thirds from the top, just above the lower third (the round part where the seeds are). Halve the lower part of the squash and scoop out the seeds (save them for another recipe), then slice and set aside. Stand the flat end of the neck of the squash on a chopping board and carefully slice vertically into long strips that resemble wide lasagne sheets, about 3-5mm thick.

Arrange the squash slices over one or two large baking trays, drizzle with 1 tbsp olive oil, then season and toss to coat. Roast for 15 mins. Put the onions in a second smaller roasting tin and drizzle with 1/2 tbsp olive oil, season and toss to coat. Put the onions in the oven and cook everything a further 10-12 mins until softened and caramelised. Remove the onions and squash from the oven and set aside.

Put the spinach in a microwavable bowl and microwave on full for 2 mins, stirring after 1 min, or put in a colander and pour over boiling water to wilt. Press down to remove as much water as possible. Roughly chop the spinach and put in a large bowl with the sundried tomatoes and roasted onions. Season to taste.

Mix the ricotta, quark, 75g of the grated parmesan and the beaten eggs together in another bowl.

Cover the bottom of the prepared dish with a layer of squash and evenly spread a third of the ricotta mixture over the top. Scatter over half of the spinach mixture, then more squash, a layer of ricotta, a second spinach layer, then the remaining squash – you might not need it all. Top with the last of the ricotta and scatter over the remaining parmesan and cheddar or mozzarella.

Bake for 45-55 mins until the top is golden brown. Leave to cool for 10 mins before serving. Once completely cool, can be frozen for up to two months. Defrost overnight and reheat in the oven until piping hot.